Ambulances are expensive enough that people are hesitant to call them, sometimes even in life threatening situations.
And if the person is unsure whether the situation is critical, they might try to "sleep it off" rather than driving or getting a ride, because ER is also kind of expensive and you could be stuck there all day.
And if the person is unsure whether the situation is critical, they might try to "sleep it off" rather than driving or getting a ride, because ER is also kind of expensive and you could be stuck there all day.